Differential cross sections for π + p elastic scattering were measured for seven incident energies from 65 to 140 MeV at laboratory scattering angles between 93° and 165°. The results are compared with previous results of Bertin et al. and the phase-shift analysis of Arndt and Roper. Agreement between the phase-shift analysis and the data is good.
ABSOLUTE NORMALIZATION UNCERTAINTY = 2.4 PCT.
ABSOLUTE NORMALIZATION UNCERTAINTY = 2.0 PCT.
ABSOLUTE NORMALIZATION UNCERTAINTY = 1.4 PCT.
Rapidity distributions of protons from central $^{197}$Au + $^{197}$Au collisions measured by the E895 Collaboration in the energy range from 2 to 8 AGeV at the Brookhaven AGS are presented. Longitudinal flow parameters derived using a thermal model including collective longitudinal expansion are extracted from these distributions. The results show an approximately linear increase in the longitudinal flow velocity, $<\beta\gamma>_{L}$, as a function of the logarithm of beam energy.
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We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at \sqrtsNN=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for $5\lt\pT\lt12$ GeV/c. The collision energy dependence of the yields and the centrality and \pT dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of \pT-dependent suppression, which may be expected from models incorporating jet attentuation in cold nuclear matter or scattering of fragmentation hadrons.
Inclusive invariant pT distributions of (h+ + h−)/2 for centrality-selected Au+Au and p+p NSD interactions. Hash marks at the top indicate bin boundaries for pT>4 GeV/c.The invariant cross section for p+p is indicated on the right vertical axis.
R200/130(pT ) vs. pT for (h+ + h−)/2 for four different centrality bins. The overall normalization uncertainty is +6−14% for the 40-60% bin and is negligible for the other panels. Calculations are described in the text.
RAA(pT) (Eq. 1) for (h+ + h−)/2 in |η|<0.5, for centrality-selected Au+Au spectra relative to the measured p+p spectrum. The p+p spectrum is common to all panels. Calculations are described in the text.
Momentum spectra of charged pions over nearly full rapidity coverage from target to beam rapidity have been measured in the 0-5% most central Au+Au collisions in the beam energy range from 2 to 8 AGeV by the E895 Experiment. Using a thermal parameterization to fit the transverse mass spectra, rapidity density distributions are extracted. The observed spectra are compared with predictions from the RQMD v2.3 cascade model and also to a thermal model including longitudinal flow. The total 4$\pi$ yields of the charged pions are used to infer an initial state entropy produced in the collisions.
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We report on the rapidity and centrality dependence of proton and anti-proton transverse mass distributions from Au+Au collisions at sqrt(sNN) = 130GeV as measured by the STAR experiment at RHIC. Our results are from the rapidity and transverse momentum range of |y|<0.5 and 0.35 <p_t<1.00GeV/c. For both protons and anti-protons, transverse mass distributions become more convex from peripheral to central collisions demonstrating characteristics of collective expansion. The measured rapidity distributions and the mean transverse momenta versus rapidity are flat within |y|<0.5. Comparisons of our data with results from model calculations indicate that in order to obtain a consistent picture of the proton(anti-proton) yields and transverse mass distributions the possibility of pre-hadronic collective expansion may have to be taken into account.
$p$ differential yield. Systematic uncertainties are $\pm$10%.
$\bar{p}$ differential yield. Systematic uncertainties are $\pm$10%.
Rapidity distribution of $p$. Combined statitiscal uncertainty and systematic uncertainty from PID contramination. Systematic uncertainties from the track reconstruction efficiency are $\pm$25%.
We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high $p_T$) in minimum bias and central d+Au collisions at $\sqrt{s_{NN}}$=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high $p_T$ previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.
Uncorrected charged particle multiplicity distributions measured in −3.8 < $\eta$ < −2.8 (Au-direction) for d+Au collisions. Points are for minimum bias (triangles) and peripheral (circles, ZDC-d single neutron) collisions. Both are normalized to the total number of d+Au collisions. Histograms are Glauber model calculations.
Inclusive $p_{T}$ distributions for minimum bias and central d+Au collisions, and non-singly diffractive p+p collisions. Hash marks at the top indicate bin boundaries for $p_{T}$ > 3.8 GeV/c.
$R_{AB}(p_{T})$ from Eq. 1 for minimum bias and central d+Au collisions, and central Au+Au collisions. The minimum bias d+Au data are displaced 100 MeV/c to the right for clarity. The error bars are the quadrature sum of the statistical and point-to-point systematic uncertainties. The bands show the normalization uncertainties, which are highly correlated point-to-point and between the two d+Au distributions.
We present STAR measurements of the azimuthal anisotropy parameter $v_2$ and the binary-collision scaled centrality ratio $R_{CP}$ for kaons and lambdas ($\Lambda+\bar{\Lambda}$) at mid-rapidity in Au+Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV. In combination, the $v_2$ and $R_{CP}$ particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish $p_T \approx 5$ GeV/c as the value where the centrality dependent baryon enhancement ends. The $K_S^0$ and $\Lambda+\bar{\Lambda}$ $v_2$ values are consistent with expectations of constituent-quark-number scaling from models of hadron fromation by parton coalescence or recombination.
The minimum bias (0-80% of the collision cross-section) v2(pT) of K0s. Errors listed include statistical and point-to-point systematic uncertainties from the background. Additional non-flow systematic uncertainties are approximately -20%.
The minimum bias (0-80% of the collision cross-section) v2(pT) of Lambda+Lambdabar. Errors listed include statistical and point-to-point systematic uncertainties from the background. Additional non-flow systematic uncertainties are approximately -20%.
The minimum bias (0-80% of the collision cross-section) v2(pT) of charged hadrons. Errors listed include statistical and point-to-point systematic uncertainties from the background. Additional non-flow systematic uncertainties are approximately -20%.
Transverse momentum spectra of charged hadrons with p_T < 8 GeV/c and neutral pions with p_T < 10 GeV/c have been measured at mid-rapidity by the PHENIX experiment at RHIC in d+Au collisions at sqrt(s_NN) = 200 GeV. The measured yields are compared to those in p+p collisions at the same sqrt(s_NN) scaled up by the number of underlying nucleon-nucleon collisions in d+Au. The yield ratio does not show the suppression observed in central Au+Au collisions at RHIC. Instead, there is a small enhancement in the yield of high momentum particles.
Midrapidity $p_T$ spectra for charged hadrons.
Midrapidity $p_T$ spectra for $\pi^0$.
Nuclear modification factor $R_{dA}$ for $\pi^0$ in the PbGl and PbSc calorimeters in minimum bias $d$+$Au$.
Pion-kaon correlation functions are constructed from central Au+Au data taken at $\sqrt{s_{NN}} = 130$ GeV. The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e. transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.
Pion-kaon correlation functions and ratios of correlation functions. Errors are statistical only.
Pion-kaon correlation functions and ratios of correlation functions. Errors are statistical only.
Pion-kaon correlation functions and ratios of correlation functions. Errors are statistical only.
The transverse mass spectra and mid-rapidity yields for $\Xi$s and $\Omega$s plus their anti-particles are presented. The 10% most central collision yields suggest that the amount of multi-strange particles produced per produced charged hadron increases from SPS to RHIC energies. A hydrodynamically inspired model fit to the spectra, which assumes a thermalized source, seems to indicate that these multi-strange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to $\pi$, K, p and $\Lambda$s.
$m_T$ spectra of $\Xi^-$ and $\bar{\Xi}^+$ for 0-10% centrality. Errors listed here are the quadrature sum of statistical and point-to-point systematic uncertainties. There is an additional overall $m_T$-independent systematic uncertainty of 10%.
$m_T$ spectra of $\Xi^-$ and $\bar{\Xi}^+$ for 10-25% centrality. Errors listed here are the quadrature sum of statistical and point-to-point systematic uncertainties. There is an additional overall $m_T$-independent systematic uncertainty of 10%.
$m_T$ spectra of $\Xi^-$ and $\bar{\Xi}^+$ for 25-75% centrality. Errors listed here are the quadrature sum of statistical and point-to-point systematic uncertainties. There is an additional overall $m_T$-independent systematic uncertainty of 10%.
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